This invention relates to a paint composition that contains a particular type of ferrophosphorus. The ferrophosphorus used in the paint compositions of this invention contains relatively high concentrations of vanadium and chromium.
In the production of phosphorus and various phosphates, rocks high in phosphate content are ground, washed and formed into nodules. The nodules are heated in an arc furnace with coke and sand to reduce the phosphates to elemental phosphorus. The elemental phosphorus distills off and a product known as ferrophosphorus, a mixture of compounds of iron and phosphorus, forms beneath a layer of slag. The ferrophosphorus is a by-product which has been used in paints, welding compositions, and as a source of phosphorus in making steel.
Zinc dust is included in paint compositions for the purpose of reducing the corrosion of steels that the paint is applied to. The zinc is effective because it corrodes before the iron in the steel does and acts as a sacrificial metal. Ferrophosphorus is much less expensive than zinc and it has been found that some of the zinc in these paints can be replaced by ferrophosphorus without significantly reducing the effectiveness of the paint. Until now, ferrophosphorus that has been used for this purpose in paint has come from phosphate rock mined in the eastern portions of the United States.